Installation and Operation Manual of QIBR Slewing Bearings

Handling before Slewing Bearing Installation

1.Rust Prevention and Package

The inner and outer surfaces of the slewing bearing are coated with dual-purpose oil for rust prevention and lubrication. The slewing bearing is pack with plastic film and wrapped with braided tape. For large-size slewing bearings, the outer surface needs to be wrapped with plastic clothes. Small size precision slewing bearing would be packed again with wooden box.

2.Transportation

The slewing bearing should be placed horizontally as much as possible during transportation, only slight inclination and vibration are allowed, and collision should be avoided. After unpacking, screw the lifting bolts into the lifting holes of the inner ring or outer ring to transport the bearing to the installation location.

3.Storage

(1)The rust proof life of the slewing bearing before opening the package is 12 months, and please do not open the package while storing. Maintenance work, like the raceway, outer surface and tooth surface of the slewing bearing should be done with rust proof treatment, is required if the slewing bearing is not installed after more than 12 months.

(2)The slewing bearing should be placed horizontally on a dry and flat location.

(3)The slewing bearing should be stored separately from chemicals and other corrosive items.

(4)If multiple sets of slewing bearings are stacked together, at least three wooden blocks with equal height and uniform distribution should be placed between every piece of slewing bearing in the circumferential direction, and the upper and lower blocks should be placed at the same position.

Installation of The Slewing Bearing

1.Requirements for mounting base

(1)The mounting base of the slewing bearing should undergo internal stress relief treatment after the welding or casting process. The surface of the matching mounting base should be machined to remove bur and sundry. The mounting base should have sufficient rigidity.

(2)The mounting base surface should be flat, dry, clean without lubricants. For continuous surfaces that cannot be machined, injection molding should be used to ensure the accuracy of mounting base.

2.Preparation before installation

(1)When unpacking the slewing bearing before installation, it is necessary to check if the bearing rotates flexibly and if the seal is intact, replace the seal if not.

(2)The slewing bearing raceway quenching soft area (outside marked "s" or filling plug) should be placed in the no-load-area or not-frequently-loaded area.

(3)Check if the gears mesh properly with each other before tightening up the mounting bolts to ensure that the meshing clearance meets the gear accuracy requirements. 

Connection Bolt 

1.The connection bolt used for the slewing bearing should have high strength. Appropriate strength grade of bolt should be used according to the stress, and the strength grade shall not be lower than Grade 8.8. Adopt the nut with the strength grade which is suitable for the bolt.

2.When installing bolts, tempered flat washers should be used, and spring washers are prohibited.

3.After the slewing bearing is positioned in radial direction, use a torque wrench to tighten up the bolts in a crosswise pattern, and check the free rotation of the slewing bearing at the same time.When tightening up the bolt, sufficient pretightening force should be guaranteed, which is 60%-70% of the yield limit of the bolt material, and the pretightening load of the bolts should meet the relevant requirements.

Lubrication and Maintenance

1.A small amount of grease is filled in the raceway before it leaves the factory. When using slewing bearing, new grease should be filled according to different working conditions.

2.The slewing bearing should be lubricated regularly, usually every 50-100 hours. However, in case of special working environments, such as tropical areas, high humidity, dust, large temperature changes and long continuous work, the lubrication should be done regularly in a shorter period. In addition, it is necessary to fill new grease before and after the machine stops running for a long time. During every time of lubrication, the raceways must be filled fully with grease until it seeps out from the seal. While filling grease, turn the slewing bearing slowly so as to make the grease is filled evenly.

3.Debris shall be removed from the gear surface frequently and corresponding lubricating grease shall be applied.

4.After the first 100 hours of operation of the slewing bearing, the preload of the bolts should be checked. Later, it should be checked after every 500 hours of operation to ensure the sufficient preload.

5.Pay attention to the operation condition of the slewing bearing during using, in case of noise, impact, or sudden increase of power, stop the machine immediately to solve the problem. Disassemble to inspect slewing bearing if necessary.

6.Check if the seal is intact frequently, replace it immediately if any damage found, and reset in time if it falls off.